Hanging political signs on one's music is a simultaneous act of recklessness and courage: It's bound to alienate the unsympathetic even as it gives momentum to the cause. That said, last Thanksgiving's Carnegie Hall performance featuring Meg Christian and Cris Williamson was such pure musical magic that it transcended politics, sexual or otherwise.

The double recording, "Meg/Cris at Carnegie Hall," is clean and crisp and true to the purpose of the concert, a celebration of the 10th anniversary of the once-struggling feminist label, Olivia. The two women's voices blend with such dulcet compassion and emotional strength that the result is what every live album should be: as good as being there.

Barely into the second cut, Margie Adam's "Beautiful Soul," it's apparent that Christian and Williamson are comfortably within that rare frame of musical perfection, and they know it. Christian's "Can't Turn Back" soars, Williamson's "Doin' Time" and "Texas Ruby Red" churn and simmer, and the nine-minutes- plus medley on Side Four flashes through the scenery of the heart like a well-stoked locomotive.

"If I Could Only Win Your Love" is not so much afterthought as anticlimax, particularly since even these fine voices cannot surpass Emmylou Harris' version. And "Ain't No Mountain High Enough" -- well, why attempt to repaint the Sistine Chapel? Still, these are tiny twinges in an album whose overall effect is vibrant with joy. ON RECORD, ON STAGE THE ALBUM MEG CHRISTIAN/CRIS WILLIAMSON -- Meg/Cris at Carnegie Hall (Second Wave LF933). THE SHOW SISTERFIRE, Saturday from noon till 7, with Meg Christian scheduled sometime after 4, at Takoma Park Junior High, 7611 Piney Branch Road, Silver Spring.